1. Field of the Invention
The present invention relates to a method of manufacturing an electronic component using a lamination chip size package (CSP), which is a type of CSP, in which a resin film is buried by performing heat pressing on an electronic functional element such as a surface acoustic wave (SAW) element bonded to a substrate.
2. Description of the Related Art
In the related art, in order to attain a compact and low profile package of a SAW filter, chip size packages (CSPs) with various kinds of structures have been developed. It is required for the CSP of the SAW filter to be sealed with a resin with a space formed around the vibration portion of the filter to allow for unhindered vibration of the SAW element.
As for a method of manufacturing such a resin-sealed package, a heat pressing process is known. Japanese Unexamined Patent Application Publication No. 2003-17979 and Japanese Unexamined Patent Application Publication No. 2003-32061 disclose a sealing technology that uses the heat pressing process. In these publications, a SAW element is mounted on a packaging substrate by flip-chip bonding so that a vibration space is formed between the packaging substrate and the SAW element attached to the packaging substrate, and the mounted SAW element is then subjected to resin sealing by the heat pressing process.
However, during the sealing by the heat pressing process, voids due to air bubble entrapment tend to occur, thus causing the sealed state to be unstable. For example, there has been a tendency that, due to degradation of thermal stability during reflowing of solder, or moisture absorption over time, degradation of characteristics over time of the sealed SAW element, occurred. Moreover, when sealing was implemented in a vacuum, it was possible to prevent voids from occurring, however, a large-scale apparatus for placing the entire system in a vacuum has been required.